This invention relates to sheet-form fastening members of synthetic resin and to methods and machines for their manufacture.
An important aspect of the invention concerns hook fastener members for hook and loop fastening. These are formed of synthetic resin in running lengths. Typically there are multitudes of fastener elements, i.e. hundreds or even thousands of discrete hook elements per square inch. These are typically arranged in neat rows in the machine direction, i.e. in the direction in which the forming system produces the product.
These hook elements stand discretely from at least one side of an integral web-form base. The base forms the means of attachment of the fastening member to the article that carries it.
Fastener members with fields of such hooks typically have a pleasing, uniform, commercially acceptable appearance and are widely found in consumer and industrial products.
In a preferred method of manufacture, molding rolls are used in the process shown e.g. in Fischer U.S. Pat. No. 4,794,028. This process produces hook fasteners of commercial appearance in which the rows of hooks are straight and the spacing between the hook elements in both directions is regular.
Mold rolls for forming preferred fastening members of this kind typically comprise a series of thin circular plates, with mold plates alternating with spacer plates. Peripheries of the individual molding plates are machined with cutouts to define small hook profile cavities. The group of plates is held so their peripheries cooperate to define the surface of the roll. Because a large number of such plates is required and the plates must be carefully held in alignment, such mold rolls have been expensive to produce and maintain and have typically been confined to short lengths. The width of the product produced has been correspondingly restricted.
Conventional fastener materials produced in this way have been less than one or two feet in width and have had a web thickness between the hooks greater than 0.005 inch, typically 0.008 inch or more. Typically, in this method of manufacture, the hooks face in the machine direction or in the opposite direction, with the consequence that their major peel and shear strengths have been similarly oriented.
Other advantages and features will be apparent from the following description and claims.